Antenna with enhanced gain

Abstract

The present invention will yield enhanced gain over a conventional antenna system by taking advantage of combining directional antennae. In one embodiment, the invention utilizes four 10 dB dipole, vertically-polarized, omni-directional antennae having a reflector added to each one to limit the horizontal beamwidth to 90° and increase the gain to 16 dB. The vertical beamwidth remains at 7°. By utilizing four of these antennae and utilizing power combining hybrids to connect each of the two opposed antennae together, excess gain over a 10 dB omni-directional system will be obtained. The effective antenna gain is equal to the directional antenna gain minus the omni-directional antenna gain minus the hybrid loss. Thus, the vertical beamwidth and physical height of the antenna are preserved with the increase in gain at the cost of a little antenna complexity.

I claim: 
     
       1. An antenna system having enhanced gain comprising: at least N directional antenna combining to cover a 360° horizontal beamwidth sector and having an established vertical beamwidth, each individual antenna including an omni-directional antenna and a reflector element to limit the horizontal beamwidth of the associated omni-directional antenna to cover no more than a 360°/N beamwidth sector where N=an even number ≧2;   a power combiner hybrid coupled to each opposed pair of antennae for combining the signals from the opposed antennae; and   a single channel diversity receiver coupled to the power combiner hybrids for adjusting the phase and amplitude of the signal from each combiner hybrid for constructively combining the signals.   
     
     
       2. A system in claim 1 wherein N=4. 
     
     
       3. A system in claim 1 wherein N=6. 
     
     
       4. A system as in claim 1 wherein each reflector limits the horizontal beamwidth of its associated antenna to no more than 90° without disturbing the vertical beamwidth. 
     
     
       5. An antenna system having enhanced gain comprising: at least N directional antennae combining to cover a 360° horizontal beamwidth and having an established vertical beamwidth, each individual antenna including an omni-directional antenna and a reflector element to limit the horizontal beamwidth of the associated omni-directional antenna to cover no more than a 360°/N beamwidth sector where N=an even number ≧2;   a power combiner hybrid coupled to each opposed pair of antennae for combining the signals from the opposed antennae;   a power splitter coupled to the output of each combiner hybrid and producing at least n output signals where n=the number of frequencies to be received;   n single channel diversity receivers individually coupled to one of said at least n output signals from each power splitter to accommodate one of the n frequencies.   
     
     
       6. A system as in claim 5 wherein n=2.